The invention relates to an apparatus and method for packing articles into cases, and particularly, to the packing of articles into cases using an apparatus and method having a continuous motion in which successive slugs or groups of moving articles are continuously picked up and transferred into moving cases.
In the art of case packing, large numbers of articles must be grouped and packaged rapidly by an apparatus that will function dependably without damage to the articles processed. Case packing apparatus has been generally categorized as either intermittent case packing or continuous case packing. Most recently, attention has been directed to continuous case packing in order to increase production. However, the continuous case packing has brought increased problems with handling the processed articles without damage.
In the continuous case packing apparatus, articles conveyed in at least one row of articles are divided up into slugs or groups of articles which are fed to a pick-up position. The slugs of articles are picked up at the pick-up position by article grippers carried by an orbital handling conveyor. The slugs are transferred to a case loading position where the grippers release the slug of articles into a case. The articles can be released either simultaneously or sequentially as the case is conveyed beneath the slug of articles. Apparatus of this type may be either of the "drop packer" type or "placement packer type". In the drop packer type, the articles are allowed to drop at least a small distance into the case after release. In the placement packer type, the drop, if any, is minimal and the articles are essentially placed gently onto the bottom of the case.
Various case packers, generally of the continuous motion type, using a vertical orbital conveyor are shown in U.S. Pat. Nos. 5,212,930; 4,541,524; and 4,294,057. The first patent shows depositing the articles sequentially and individually, rather than as slugs, into partitioned cases without positively gripping the articles. The latter two patents use gripper devices to grip the articles.
U.S. Pat. No. 4,457,121 discloses a continuous motion bottle packer wherein a plurality of grids are mounted individually on spokes of a vertical wheel so that each grid moves through an article infeed position where groups of articles are fed into the grid without interrupting the forward speed. The wheel moves the grids and articles to a lower discharge position where the groups of articles are dropped into a case without interrupting the motion of the articles in the direction of a case conveyor which indexes the cases. While continuous, this bottle packer generally of the drop packer type wherein the bottles are dropped into the case through resilient fingers. Also, a control problem is created due to the necessity of varying the speed between the rotating grids and the linearly moving cases in order to coordinate reliable timing of the grid and the case at the case packing position for reliable insertion of the slug. Angular and horizontal accelerations of the articles and their contents are also encountered due to the rotary wheel motion during the transfer which may be detrimental to the article and/or contents.
Continuous motion case packers are also known having a vertical rotating wheel which carries a plurality of arms which include two articulating links. A set of article grippers is carried on the ends of the articulating arms. The relative angular positions of the articulating links are controlled to place the article grippers over a slug of articles at a pick-up position, positively grip the slug, and lower the slug to a case packing position where moving cases are indexed with the moving gripper sets. However, during the angular descent from the pick-up position to the case packing position, both horizontal and vertical accelerations are encountered by the articles which are gripped only at their tops or necks. U.S. Pat. No. 5,313,764 discloses a continuous motion case packer wherein the articles and cases are indexed and conveyed on parallel conveyors arranged one above the other. Steering bars which correspond to the bars of a parallelogram move a gripper set, in the same general direction as the article and case conveyance, between the pick-up and case packing positions. However, again, horizontal and vertical accelerations are produced on the pick-up head and the articles, and timing becomes a problem.
Continuous case packers are also known in which a horizontal rotary carousel is used to move vertically reciprocating gripper sets in a horizontal plane. The reciprocating gripper sets pick up a slug of articles at one position and transfer the slug of articles to a second position where the gripper set is lowered to deposit the articles into a case. However, the disposition of the rotary carousel in a horizontal plane requires an inconvenient floor lay-out which also occupies a large amount of floor space. Typically, parallel conveyor arrangements are needed for the articles and the cases adding to the floor space problem. The path of the gripper sets between the slug pick-up position and the case packing position is also typically curved producing angular accelerations and forces on the articles, and the curved article path intersects the path of the conveyed case only for a brief interval. In various of the rotary carousel types, it is known to deposit the articles by lowering the articles, already gripped by the gripper set, through resilient fingers that guide the articles into partitioned cases.
Case packers, generally of the intermittent type, are shown in U.S. Pat. Nos. 3,553,932 and 3,505,787 which also disclose using combinations of a lifting head having suction cups and bottle grids having pockets for picking up containers and depositing them into cases. The containers and the cases are conveyed on parallel conveyors rather than in-line conveyors, and the transfer from the pick-up position to the case loading position is lateral, or transverse, to the flow of containers and cases. U. S. Pat. No. 2,277,688 discloses another case packer using an arrangement of a gripper set and a bottle guide set to package the containers into a case. These type of case packers are generally non-continuous as compared to the continuous motion in-line transfer case packers described above where neither the flow of articles nor the flow of the cases is stopped during operation of the packer.
Accordingly, an object of the invention is to provide an improved continuous motion case packing apparatus and method.
Another object of the invention is to provide a continuous motion case packing apparatus and method in which slugs of articles are picked up, transferred, and deposited in a case in a reliable, continuous manner without damage to the articles or their contents.
Another object of the invention is to provide a continuous motion case packing apparatus and method having a slug feeder which can be adjusted to change over the size of the slug in a quick and easy manner without the need of extensive machine down time and substitution and reassembling of mechanical parts.
Another object of the invention is to provide a continuous motion case packing apparatus and method in which slugs of articles are picked up and transferred to a case packing station over a horizontal linear transfer path in which the horizontal speed of the slug is constant, and depositing into a case is done in a gentle vertical motion.
Still another object of the invention is to provide a continuous motion case packing apparatus and method having a grid head which includes a matrix of grid finger chutes in which slugs of articles are picked up from overhead, and retained with positive locking within the chutes for transfer and deposit into a case in a reliable and continuous manner.
Yet another object of the invention is to provide a continuous motion case packing apparatus and method in which a revolving carriage moves a plurality of transfer arms having sliding article pick-up heads in a vertical plane, closed curve path in a manner that the slugs of articles conveyed in the same plane are picked up, transferred, and deposited into indexed cases conveyed in the same plane in a reliable, continuous manner, and with a minimum amount of floor space.